In my experience, it's a player issue. A large chunk of the player base has no desire to learn how to be good and wants no expectations on their performance, and is unwilling to change. Dungeons, 24-mans, and story versions of raids and primals are built for them. If someone wants to learn, they will seek knowledge from other players or outside resources and learn, and they will join the serious players in being good at their job. The players who have no desire to learn their job will always be problems.